Demon in the Night
by randomplotbunny
Summary: Mycroft just wants to keep Sherlock safe, and then he meets a demon...
1. Chapter 1

**Disclaimer: Neither Sherlock or Black Butler belong to me. I am just a lowly fangirl playing around with things I shouldn't really touch.**

Mycroft gazed deep into the smouldering embers of his dying fire as he took another sip of his expensive scotch and thought about his little brother.

Sherlock would be the death of him.

With a sigh, the most powerful man in the British government wished for a way to keep his annoying and danger seeking git of a brother safe. He would give anything- ANYTHING!- to protect Sherlock from his own destructive behavior.

"Anything?" Not showing any outward signs of his sudden startlement, Mycroft began to look for the source of the quiet voice that shouldn't be in the room with him.

"Looking in the wrong place I'm afraid." Turning towards the fireplace Mycroft could just make out a pair of blue eyes staring at him from within the flames.

"Oh! Would you prefer something a bit more ordinary then?" The voice teased, clearly amused by Mycroft's shock.

The embers stirred and a figure climbed out of the flames and sat in a chair near the 'minor' government official. A taunting smile stretched- his? its?- mouth.

Looking over the figure Mycroft was disappointed in what he saw: short, stocky build, sandy blonde hair turning to grey in places, the blue eyes that he had already noted, the uniform of an army Captain with an added badge to show he was a doctor and a fatal looking bullet wound in his left shoulder.

Nothing to indicate how he had gotten into Mycroft's secure flat, or how he hadn't been terribly burned by the flames- dying fire or not, those embers were hot!

If he were a lesser man he might think he had been drugged, or was going insane, but he knew better. With a brother like Sherlock, one had to become VERY aware of their surroundings and know their own mind thoroughly.

These musings took less than a breath to cross his mind and he quickly focused back on the... person's amused eyes.

"I heard you. You would do 'Anything!' to protect your brother." Giving Mycroft a friendly smile that did nothing to hide the predatory gleam of his eyes, the 'man' laid a hand on his breast.

"I'm 'Anything'." As the eyes flashed a momentary red, Mycroft finally understood what he was faced with: a demon.

Deciding to see where this would go, he downed the rest of his scotch in a hand that he would never admit shook; and turned a level look upon his otherworldly visitor.

"Your kind only come when called. I did not call you." A lazy smile played across the demon's features.

"Oh, but you did Mycroft. You did. I was just leaving the life my last Master inflicted on me," the demon indicated the large wound in his shoulder- Mycroft could now see that it was in fact completely healed- and continued, "when I heard you make your wish."

"People make wishes all the time, that is no reason to appear to them and offer your 'services'."

"True. But then, so few people actually mean it when they saw that they would do anything for what they want; and I happen to prefer the taste of selfless souls, especially when they normally are not so inclined." Giving Mycroft a pointed look the demon let the genius figure it out. A moment later he wasn't disappointed.

"You want my soul in exchange for my brother's safety?" He phrased it carefully, no need to give this monster everything at once.

"Yes. I would take care of Sherlock's health and well-being in exchange for your soul." The creäture had the audacity to smirk after revealing that it knew the name of the younger Holmes brother.

"I would keep him happy and out if danger, or at least, out of life threatening danger. And I would protect him from everything I could not prevent." Mycroft had to admit that it sounded too good to be true, and so knew that there had to be a large trap in there somewhere.

"And just how long would you look after my brother? Until I died? Or until you killed me?" Smiling in proud way, as if Mycroft were a puppy that had just done a complicated trick, the demon nodded approval.

"Very smart- genius even! So few mortals realize the fallacy of language, or just how a contract can be worded to the demon's benefit." Sitting straighter the demon inclined his head to indicate a shared secret.

"Take my most recent Master for instance: Bill Murry. His brother kills their Captain because the man refused his sexual advances, and then Bill begs me to take on the life of the dead doctor so no-one will know what had happened. The fool never said a word about his or his brothers' lives!" The demon chuckles darkly and Mycroft can imagine what had happened.

"I strung them along for a few months until they relaxed, and then I staged a fire fight with a group of locals. No-one noticed a couple of extra bodies in the mix of blood and death, but my Master got exactly, and only, what he had asked for: his brother got away with murder." Giving Mycroft a calculating look the demon's smile grew.

"I'll tell you what: you write up the contract, and if I like it we can make a deal." Standing the demon headed back towards the fireplace.

"I'll return tomorrow night for your answer, shall I?" Not waiting for a response, the demon entered the fires and was gone.

Getting himself another scotch the elder Holmes contemplated the demon's offer.

He would not take it- he could not! He would not barter his soul to an untrustworthy demon!

Just as he made up his mind his phone rang. It was one of the security details he had following Sherlock.

Sherlock had run into a building full of human traffickers and was now in the hospital being treated. He had been shot at and was hit once- just above the left knee, a through and through, not very much damage done- and had to have several grazes stitched.

Placing his phone down, Mycroft resigned himself to not getting any sleep that night- he had a carefully worded contract to write up.


	2. Chapter 2

**Disclaimer: So not mine.**

Mycroft rubbed at his right wrist. The demon's mark was well hidden by his cuffs, but no matter what he told himself it always felt like it was burning slightly.

Looking over the video feed from the hidden cameras in Sherlock and the demon's- call it John Watson, he reminded himself, we can't have Sherlock getting too suspicious of why you don't like his new 'friend'- flat, Mycroft let himself relax a little.

His brother was safe- at least for the moment- and was being well taken care of. He was even eating without coercion!

When the demon's eyes unerringly met his through the screen and gave him a smirk, he decided it was time to retire for the night.

As he crawled into bed he again thought over that night three weeks ago:

The demon appeared to him as promised and Mycroft handed it a thick stack of papers.

"Not the subtle type, are you?" It teased.

"Not when it comes to my brother's safety." The tall ginger human assured the desert uniform wearing demon. With a smirk the creäture settled down to read the contract he had been presented with.

"Protection of your brother until his natural demise. Non retaliation on yourself until and unless Sherlock dies of natural causes before you. No killing those in close contact with either your brother or yourself. No telling your brother about my true nature or the nature of my contract to you." Smiling at that last bit the demon continued to look over the presented contract.

"I can have your soul upon your natural death, or your death at the hands of your enemies. Conspiring with your enemies- or anyone else- to cause your untimely death with negate the contract and I get nothing. The contract extends beyond your death, and I will continue to look after Sherlock until his natural demise." The demon spoke softly to himself as he read through the stack of papers.

"Everything seems to be in order. I only have one small change to make." The lazy ease of the demon was not shared by the tense Mycroft.

"And what would that be?" He asked cautiously.

"You have in here that I am not allowed to consume souls while contracted to you. That just won't do. Unlike other demons I don't choose to starve myself between meals." Looking Mycroft up and down, the demon tried not to laugh.

"You can understand the importance of a regular diet, can't you?" At Mycroft's scowl the demon finally did laugh.

"Souls like yours are a rare treat for me, otherwise I mostly feast on the common herd." Taking a piece of paper and pen from the large desk in the corner the demon wrote out a replacement page for the one he found objectionable.

"This should cover all your bases that you took such pains to be explicit about presenting, and will also allow me to hunt for my regular fare." Handing the page to the genius he settled back into the chair he had taken as his own the night before.

Taking several minutes- he wanted to be absolutely sure the demon hadn't made itself a loophole of some kind- Mycroft finally agreed to the terms the creäture had presented.

"Fine. Then we have a deal? My soul in exchange for Sherlock's long life and safety?"

"Of course. Your soul in exchange for everything you put in this contract." Not knowing if he was being tricked or not with the demon's choice of wording, Mycroft held his hand out to seal the deal- after all, he had been the one to write that contract.

Instead of excepting the offered hand, the demon undid the cuffs of the expensive suit and pushed the sleeve up to reveal an unblemished wrist and forearm.

"A proper demonic contract requires a seal." So saying, the demon pressed their wrists together.

Trying to repress a scream at the sudden burning pain, Mycroft gasped when it was suddenly gone. Looking down at his wrist he saw a circular tattoo, it matched the one now adorning the demon's wrist.

"Now I must be off." It said cheerfully.

"You were fairly vague on how I was to approach your brother, so I do need to figure out the best way to do so." Turning away with a smirk, it headed back towards the fireplace to make its exit.

"You don't even know where he is." Waving his concerns away the demon stepped into the fire and was gone.

Two days after he was released from the hospital Sherlock Holmes was introduced to Dr. John Watson.


	3. Chapter 3

**Disclaimer: I own nothing recognizable!**

When he had taken the form of the late Captain he had also done a great deal of research into the man's life, so that he could pass himself off seamlessly as the good doctor.

He had been pleased to note that- upon examining the habits and personality of the younger Holmes brother- he would be able to use that knowledge during this new contract as well.

He made sure to cover his tracks out of the army well- medical files, discharge papers, psychosomatic limp and a tasty therapist he would visit some late night when he wanted something to snack on- as he would be living with a deductive genius- at least a genius by mortal standards- he didn't want to give himself away too early in the game.

After all, that fool Mycroft had put nothing in his carefully worded contract about Sherlock finding out all on his own- he had also left several other juicy loopholes that could be explored at a later date and at his leisure.

But right now he was sitting on a bench, drinking horrible coffee and talking to one of the late John Watson's college friends- who also happened to have direct access to the man he needed to get introduced to.

Nimbly steering the conversation to where he wanted it to go, he waited for the appropriate moment and then repeated the line he had heard said earlier to this man.

"Who would want me as a flatmate?" The bait was taken just as he knew it would be, and 'his old friend' gave a chuckle.

"You know, you're the second person to say that to me today." Hiding his triumphant smirk behind a confused frown he led this round man to where he needed him to go.

"Oh? And who was the first?"

And then he was taken to his first face to face meeting with the man he would be babysitting for the next several years, or decades depending on how long he wanted to draw this out.

SHERLOCKSHERLOCKSHERLOCKSHERLOCK

He had come across an unforeseen side effect in his personal interactions with 'the World's only Consulting Detective': the man was utterly fascinating!

He was rude, inconsiderate, abrupt, filled with a whirlwind of energy and elegant in his movements.

He could almost come to believe the man was a demon in disguise- though a demon would do better at hiding what they were- if he wasn't completely certain the man was mortal.

And the way he had been 'tricked' into leaving his cane at that restaurant to chase down the cab- though it was a bit disappointing when Sherlock had failed to realize that the cabby was the serial killer- was absolutely brilliant, he had even felt something akin to pride in the mortal man's actions at that moment.

So when he shot the cabby later on it had been out of a genuine desire to protect, and not just a need to fulfill his contractual duties.

Yes, Sherlock Holmes would find his newly made friend, Dr. John H. Watson, standing eagerly by his side for years to come- or at least until he grew bored enough to take advantage of one of those loopholes.

_)_

_AN: Yes, I know it's short, but I promise that the next chapter will be longer!_

_And don't believe for a moment that I forgot about this story, I haven't. I've just been busy and this got shoved to the back burner for a while._

_I might take a while between updates, but trust me when I say this: I do not abandon stories! I will see this through to the end, I promise you that._

_That being said, please tell me what you think. I love reviews, they make me work harder._


	4. Chapter 4

**Disclaimer: I own nothing recognizable.**

It was late, and raining, and he didn't even know if the man he was looking for was still in business; but John was going to try and find him, for the sake of Sherlock's boredom.

It took him half the night- during which time Sherlock believed he was asleep in his room- to find the newest residence of the 'old man' he sought, but once he found it he knew that he had come to the right place.

Knock! Knock!

"Undertaker? I know you're in there, I can smell you just on the other side of the door, so open up!" The door opened a crack, just enough to show John that he was being allowed inside, and so the Demon in man form headed into the darkness and out of the street.

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"And just where are we going?" The disgruntled Consulting Detective whined as their taxi took another turn, heading them further into London's East End.

"I told you earlier." The blonde sitting next to him said as he turned curious- yet non-judgemental- eyes on his flatmate.

"Don't tell me you erased it already? Sherlock, I told you less than an hour ago!" Truthfully he was more in awe than upset- who wouldn't be with a man that could willfully forget the simplest of things on command- but he had to maintain the illusion of humanity, and that illusion dictated his being upset.

"God, Sherlock! We are going to The Undertaker's shop, like I told you before, and please don't erase it this time as I don't fancy explaining it to you once more."

"Fine. But just who is this undertaker, and why are we visiting his shop?"

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"So this is the pretty one that little Johnny was telling me about? Very pretty indeed! He, he!" Sherlock followed the excentric man in the top hat around the room with his eyes, never moving from his spot, and still pondering what John had said in the taxi ride over to this rundown shop.

"Not 'an' undertaker, 'The Undertaker'. He is an old acquaintance that I have recently retouched base with, and I thought that the two of you might just hit it off. After all, you both like playing with body parts." The Demon had then shot Sherlock a challenging look.

"But of course there is always the possibility that you won't pass his test and won't be allowed to spend time with him and the massive amount of unique and exotic information he has stock-piled." John already knew him too well, he realized in that moment, the doctor knew he couldn't turn away from the possibility of learning something new and interesting.

And he had to admit that the fact that John seemed to be trying to help him make friends with new people- no matter how doomed such a project would actually be- was quite... endearing, though of course he would never say so out loud.

And now he was in this dingy little shop, surrounded by caskets- sitting on one in fact- drinking tea out of a beaker- not nearly as good as John's was, but then so few things were- and eating a bone shaped biscuit while watching the odd proprietor move about.

He didn't want to admit it, but this man- The Undertaker, as seemed to be his only moniker- was quite intriguing.

"Very very pretty indeed, but I still don't see what I can be of help here for." It came out more as a question than a statement, and was solely directed at John.

Taking another sip of his tea, Sherlock waited for the doctor's answer as he wished to hear it himself.

"Um... I was hoping that you two might get on? Sherlock likes to solve puzzles, and you like providing information- at a price, at least." Ah, now he saw it! John had actually been trying to set him up with a new informant without letting him know that the good doctor once had ties to the Underworld!

He would have to remember to applaud John later for his dissembling skills, he hadn't picked up on anything untoward earlier.

"Yes, but can the pretty one pay? He seems far to serious to do so." As eyes- meticulously hidden by long bangs- scrutinized him, Sherlock scrutinized right back.

Before John could say a word to tell him what the mysterious 'price' would entail he had it deduced, as well as the most straight forward means of paying.

"Farfug-nugen." He said, and was met by a blank stare.

The stare held for all of three seconds.

"HA HA HA HA! HO HO HE HE, HA Ha ha ha..." And so on for several minutes.

Once he calmed down enough to where he was only partly giggling, The Undertaker wandered back over to his guests and took Sherlock's hand warmly in his own.

"I haven't laughed like that since the butler stopped coming by with his little Master. You, sir, are welcome here anytime." Backing up he plopped down on a coffin of his own and took a sip of his cold tea.

"So... is their anything you would care to know? Or was this simply a social visit as little Johnny implied that it would be?" Wanting to know just what sort of information that this new informant might provide him with, Sherlock leaned forward to ask:

"And just how did you come to be in the undertaking business, Mr. Undertaker?" As the 'old man' gave a sharp grin, John stood.

"I think you two have this well in hand, so I doubt that I am needed. I'll see you at home Sherlock, goodbye 'Taker." Leaving out the back door he took to the roof tops to meet with the one who had trailed them all the way from Baker street.

"Don't look so glum, he won't go far. He can't!" Shooting a now suspicious glare at the interesting person he had been left with- Had they walked into someone's trap? And if so, who's?- he only received a wide smile in return.

"You really haven't figured it out yet, have you?" Getting uneasy at the thought that something had passed him by without his realizing it, Sherlock prodded further into what the silver-haired man meant.

"And just what don't I know?" He finally broke down enough to ask.

The sudden loud peals of laughter that rang through the small shop did nothing to appease Sherlock's growing unease.

And the revelations about his friend and flatmate that came once the laughter died down didn't help him much either.

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The creäture he was following was fast as they raced across the roof tops of London, John could have easily caught it if he didn't know that it was trying to lead him somewhere- most likely to the one who had sent it to watch them in the first place.

As they reached the docks John became aware of a presence that he really hoped he was not being lead to, and the creäture scuttled inside of a derelict building with John not a moment behind.

Skidding to a halt, the demon came face to face with the owner of the nasty presence he had felt, much to his displeasure.

"John! I'm sooo glad you could make it! I'd had some fears that you wouldn't take my invitation you know." Giving the thing in front of him the once over, John decided to see what this was all about before he turned on his heel and left.

He had better things to do than chat with fallen Angels after all.

"You're probably wondering why I wanted you here, uh. Well you see, Johnny- I can call you Johnny can't I? It's not like that's even your real name, after all. And you can call me Jim, by the way. Hi!" The no-longer-really-an-angel Angel said as he began to saunter over to John with his hands in his pockets.

"You see Johnny, I have a venture coming up soon, and I need strong individuals like you to be a part of it. To take part in an event that will help to reshape the world as the cattle known as humanity knows it."

"And just what would my place in this venture be?" The Demon inquired as Jim drew closer.

"Oh, you know, helping to eradicate all human military and medical installations, helping to thin the herd of all the culls of society. Basically you'd be helping to enslave the human race." Bouncing on his heels, and looking very pleased with himself as if he hadn't just casually mentioned causing mass death and terror across the globe, Jim waited for John's response.

Though it wasn't one he was happy with.

"No thanks, I quite like humanity the way it is. Lots of good food, and plenty of entertainment- sometimes all in the same package. So no deal Jim." Taking a sudden swipe at the too close Angel John was surprised at how quickly the fallen-one managed to dodge him, almost like Jim had seen the attack coming.

"Hmm, perhaps you should think things over for a while. I'll be in touch, 'Doctor'." With that Jim took off in a flurry of feathers, leaving John alone with his thoughts.

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Returning to the flat later that evening, with several bags from the Tesco around the corner, John knew instantly that Mycroft was inside as well as Sherlock- and that they were both highly upset.

Pausing on the street he listened in to their fight for a minute.

"I can't believe you would sic a demon on me like this! The least you could have done is to tell me, I can think of a dozen experiments I could have been performing on a real life demon, but you had to go and try to keep him a secret!"

"Sherlock, I did it for your own good. You need protection that I just can not provide, and he was the best option I had." Deciding that a dramatic entrance would be perfect right about now he quickly made his was up the seventeen steps and through the door.

"O, hello." He said with a grin as he put the groceries away.

"John, I know you're a demon now, so you can stop the whole goody-goody attitude." Sherlock said as he sank on to the sofa with a huff.

"He can't do that little brother, he is contractually obligated to take care of you" Mycroft stated in his most pompous manner.

"Actually I'm not. At least, not any more." John said as he came into the sitting room with tea for all.

As Mycroft drew himself up for a proper tiff, John grabbed the copy of their over long contract that Sherlock had obviously swiped from his brother's flat.

Turning to the page he wanted he presented it so that both Holmes's could read the passage he wanted.

'In the event of a catastrophe that would destroy the English way of life all contractual obligations will be recended until the event has been taken care of and order restored once more.'

As the two read this Sherlock began to smirk.

"A bit vague in your wording their, My?" Relaxing just a bit as John shared his amusement, Sherlock turned to see what his brother's reaction would be.

"That will only apply if England is in danger." He tried to reason as he realized just how big a mistake he had placed in the sensitive document- if this passage was activated then the contract was null and void, and the Demon could kill him and Sherlock both and feast on their souls at his leisure!

"I was approached today by a fallen Angel named Jim, he is going to try to kill off most of humanity and enslave the rest. I'm fairly certain that this falls under the category of catastrophe." John placed the, now useless, contract on the table and stepped back to sit in his chair to drink his rapidly cooling tea.

"And just where does that leave us?" Mycroft asked as he tried to put himself between the demon he had invited in and his little brother.

"Us? Well... I'd say that it leaves us with a suspended contract, an upcoming event of apocalyptic proportions and a crazed fluff-ball that needs to be taken down." Sipping his tea slowly he stretched out Mycroft's unease a bit longer, up until Sherlock ruined the moment by giggling.

Stifling his own mirth, John gave Mycroft a very pointed look.

"This isn't the only loophole you provided me with- I could get out of our contract at anytime that I so wish- but I'm not going to exploit this one at this time." Mycroft gave him a confused look as Sherlock moved around him to sit in his own chair opposite his new-found Demon.

"And why not? Demon's are not known for being loyal out side of a contractual binding. So why would you not take this opportunity?" Mycroft asked. He could see the answers in front of him, but for once he didn't trust his own observational skills to be telling him the truth.

Tilting his mug towards Sherlock John indicated that the detective should verbalize what his brother was having such a hard time accepting.

"He likes me, My, he thinks of me as an honorary Demon. And he needs my help to take down this 'Jim' character." Steepling his fingers together, Sherlock struck his thinking pose with a rarely seen gleeful smirk on his face.

"I do believe that this case is going to rank an eleven on his scale of interest." The ginger-haired man said as he picked up the bound contract- he would be going over it very carefully, looking for any other poorly worded sections he may have accidentally put in.

"So our contract..."

"Is still in full effect, but will remain suspended until the threat Jim poses is abolished. Don't worry Mycroft, I won't let anything happen to our boy." Giving a sharp nod, Mycroft strode out of the flat before he could give in to the urge to grab his baby brother and run.

He would just need to accept that Sherlock's fate- all their fates really- now resided in the hands of a Demon. A Demon that had recently shown that it could be duplicitous, as evidenced by the loopholes within their contract.

"John?"

"Yes, Sherlock."

"If you weren't a Demon, and you weren't..." Leaning forward John rested a comforting hand on Sherlock's knee.

"Even without the contract- even if I were human- I'd still always be here for you, I will always be your friend Sherlock." Sharing a smile they then got down to the business at hand: bring Sherlock up to date on matters concerning the occult.

"And we can go talk to Undertaker tomorrow, he might be able to tell us more about Jim. Or at least let us know if there are any new rumors flying around."

"Is he a Demon too? I was so wrapped up in learning about you that I didn't even think to ask." Chuckling slightly, John reassured his friend.

"No, he's no Demon." Turning away from the tall detective, but keeping him fully in his peripheral vision, the Demon laid another shock on Sherlock that night- one of many to come.

"He's really a retired Grim Reaper." It took all of twelve seconds before a response was forthcoming.

"You mean Grim Reapers are real!" Chuckling at the indignant response, John decided then and there that even if they couldn't save the world he would find a way to save Sherlock Holmes.


End file.
